+ =嵌套的For循環使用列表理解

Question

我的代碼：

a = [[random.randint(0,10) for i in range(3)] for j in range(4)]
b = [0]*4
c = [random.random() for i in range(12)]
for i in range(len(a)):
    for j in a[i]:
        b[i] += c[j]

知道如何將其實現為列表理解嗎？

Answer 1

使用sum ：

b = [sum(row) for row in a]

編輯

b = [sum(c[i] for i in row) for row in a]

Answer 2

試試以下代碼片段：

import operator

b = [sum(map(operator.getitem,[c]*3, a_)) for a_ in a]

或與operator.itemgetter ：

b = [sum(operator.itemgetter(*_a)(c)) for _a in a]

Answer 3

抱歉，這是您要的嗎？

import random

a = [[random.randint(0,10) for i in range(4)] for j in range(4)]
b = [0 for i in range(4)]

for i in a:
    for j in i:
        b[a.index(i)] += j

print b